Aircraft galley refrigeration systems are used to refrigerate food carts, which are stored in at least one galley of the aircraft, to prevent spoilage of foodstuffs prior to providing the foodstuffs to onboard passengers. One conventional aircraft galley refrigeration system includes air chillers and cold air supply (or air ducting) systems in the galley that interface with the food carts to cool the interiors of the food carts. Another conventional aircraft galley refrigeration system includes at least one liquid chiller, a central or separate liquid recirculation unit, at least one galley air cooling unit, and a liquid plumbing system. Liquid chillers are remotely located from the galleys for chilling a heat transfer liquid that enters galley air cooling system devices. In such devices, heat is transferred from the interiors of the food carts to the liquid to keep the foodstuffs at proper storage temperature or temperatures (i.e., different galleys may store different foodstuffs, for example one galley may store a first type of foodstuff which requires one storage temperature and another galley may store another type of foodstuff or beverages which require another, different storage temperature) to prevent food spoilage.
One conventional aircraft galley refrigeration system that includes liquid chillers is illustrated in FIG. 1. As shown in FIG. 1, the aircraft galley refrigeration system 10 includes at least one galley 20, at least one remote chiller (RC) 30, and a central liquid recirculation unit (RU) 40. Although the at least one galley 20 includes three galley locations, namely Galley1 22, Galley2 24, and Galley3 26 as shown, the at least one galley 20 may include fewer or additional galley locations. Similarly, although the at least one RC 30 includes three RC locations, namely RC1 32, RC2 34, and RC3 36 as shown, the at least one RC 30 may include fewer or additional RC locations. However, the number of RCs generally corresponds with the number of galley locations in a one-to-one relationship. Each remote chiller, RC1 32, RC2 34, and RC3 36 as shown, is a self-contained refrigeration unit with a refrigerant vapor cycle system that removes heat from a heat transfer fluid. As shown, the at least one galley 20 receives low temperature heat transfer fluid from the at least one RC 30 via line 32. Also, the RU 40 receives high temperature heat transfer fluid from the at least one galley 20 via line 42. Furthermore, the at least one RC 30 receives from RU 40 the high temperature heat transfer fluid output from the at least one galley 20.
More particularly, Galley1 22, Galley2 24, and Galley3 26, which comprise the at least one galley 20, include respective heat transfer fluid inlets and outlets 22a, 22b; 24a, 24b; 26a, 26b. Similarly, RC1 32, RC2 34, and RC3 36, which comprise the at least one RC 30, include respective heat transfer fluid inlets and outlets 32a, 32b; 34a, 34b; 36a, 36b. Each heat transfer fluid inlet 22a, 24a, 26a of the galley locations 22, 24, 26 is fed low temperature heat transfer fluid by line 32. Each heat transfer fluid outlet 22b, 24b, 26b of the galley locations 22, 24, 26 exhausts high temperature heat transfer fluid to line 42 after the heat transfer fluid has absorbed the heat from cooling foodstuffs stored in the galley locations 22, 24, 26. RU 40 receives the high temperature heat transfer fluid exhausted to line 42 by the galley locations 22, 24, 26 (particularly the outlets 22b, 24b, 26b thereof) and pressurizes the heat transfer fluid. Additionally, each of the RC locations 32, 34, 36 (particularly the heat transfer fluid inlets 32a, 34a, 36a thereof) is fed high temperature, high pressure heat transfer fluid by RU 40. Each heat transfer fluid outlet 32b, 34b, 36b of the RC locations 32, 34, 36 outputs low temperature, high pressure heat transfer fluid to line 32 to work on cooling foodstuffs stored in the galley locations 22, 24, 26.
According to the foregoing, it can be appreciated that RU 40 defines a single point of failure of the system 10. That is, heat transfer fluid of the system 10 could not be sufficiently circulated between the at least one galley 20 and at least one remote chiller RC 30 if the RU 40 were to malfunction or fail. Furthermore, it can be appreciated that if heat transfer fluid were to leak from any one component of the system 10, the entire system 10 would need to be turned off so that repairs could be made. In view of the foregoing, a new aircraft galley refrigeration system would be an important improvement in the art.